How to fix a watch if it stop occasionally?

[EatPeach]

it's a simple manual wind movement (Universal 1-42). Timing, amplitude and beat error is good. (-15~-10,240~280, within 0.6) I check all the wheels and pivots, I replace the old mainspring (lurbricated by 8300). It stop occasionally and without a pattern. Sometimes it can runs for 24hours or more， sometimes it stops after few hours after winding it. When it stop shaking can not wake this one up. Adjusting time or wind up the movement can. I have no experience with this kind of trouble. Any idea what should I look for?

[oldhippy]

The most common problem is dirt. Just a speck of dirt in the movement can cause a movement to play up. A clean and oil is most likely needed. One other thing a watch movement that is not housed in a round case can be more susceptible to letting dirt in.  

[EatPeach]

15 minutes ago, oldhippy said:

The most common problem is dirt. Just a speck of dirt in the movement can cause a movement to play up. A clean and oil is most likely needed. One other thing a watch movement that is not housed in a round case can be more susceptible to letting dirt in.  

this is what happened after I serviced it. I think lurbrication wasn't the problem. As for debris, I don't really see any.

[oldhippy]

Have you tried the watch out of its case? Make sure the hands are free from each other and away from the glass. Just because you cleaned it doesn't mean its free from dirt, how did you clean it by hand or a watch cleaning machine. 

[EatPeach]

It doesnt seem to have any difference in or out of the case. I use an ultrasonic machine to clean the parts.

[Nucejoe]

Remove the hands and dial plate, bench test in wind and set position sepeartely.

[oldhippy]

I would go through the movement and check the teeth, pinons, pivots and jewels and end shake. Also check the pallets and escapement.  

[clockboy]

It needs a service and inspection

[AndyHull]

Do you have a nice straight line on the time grapher, when graphed over long periods?
Does it stop when worn on your wrist?
Does it start again when wound?

Does it feel fully unwound when it has stopped?

[EatPeach]

1 minute ago, AndyHull said:

Do you have a nice straight line on the time grapher, when graphed over long periods?
Does it stop when worn on your wrist?
Does it start again when wound?

Does it feel fully unwound when it has stopped?

1. yes

2. yes but also when it sit still

3. yes

4. sometimes

[AndyHull]

3 minutes ago, EatPeach said:

1. yes

2. yes but also when it sit still

3. yes

4. sometimes

It sounds like there is wear which is allowing the mainspring to unwind. Inspect very closely for worn teeth, worn pivots, damaged jewels, worn barrel arbour, gears that are no longer flat and true.

[EatPeach]

39 minutes ago, AndyHull said:

It sounds like there is wear which is allowing the mainspring to unwind. Inspect very closely for worn teeth, worn pivots, damaged jewels, worn barrel arbour, gears that are no longer flat and true.

Hmmm just a guess. The second wheel is fine. Before the movement stop the hands doesn't run like crazy. So it should be something concerning the winding and mainspring barrel.

[Nucejoe]

Combination of misaligned pallets and excess end shake of fork arbour, if gone unchecked can keep us guessing for quite sometime.

 

 

 

Edited August 31, 2020 by Nucejoe
Right on Andy

[rodabod]

A bad depth is another possibility (wear, excessive side-shake) and a deformed tooth.

[Tudor]

No idea if this is the problem, but how well is the canon pinion operating?

I had one that was not perfectly round (I guess) and that drag would stop the movement. 

[EatPeach]

12 minutes ago, Tudor said:

No idea if this is the problem, but how well is the canon pinion operating?

I had one that was not perfectly round (I guess) and that drag would stop the movement. 

base on how smooth it takes to set time. I dont think canon pinion is the problem.

[EatPeach]

Update:

I take the movement out and fully wind it up. I'm check how far this time it can run. If it can be constantly running and graduatly release all the power of the mainspring, then guess the problem is the hands and case

[VWatchie]

13 hours ago, EatPeach said:

Any idea what should I look for?

Judging from the many replies, I'd say you'd have to look at everything! 

 

11 hours ago, Nucejoe said:

Remove the hands and dial plate, bench test in wind and set position sepeartely.

6 hours ago, EatPeach said:

I take the movement out and fully wind it up. I'm check how far this time it can run. If it can be constantly running and graduatly release all the power of the mainspring, then guess the problem is the hands and case

Reminds me of Nuce's suggestion, but do remove the hands and the dial too. If that solves the problem you'll know for sure where to look.

[watchweasol]

Hi  I dont think there is a right or a wrong answer to this but to try and reduce the factors. Removing it from the case and removing the dial and hands  is basically stage one and if the fault persists move foreward from there by degrees.

[AndyHull]

1 hour ago, VWatchie said:

Judging from the many replies, I'd say you'd have to look at everything! 

Pretty much, yes. Nobody said this was going to be easy.

[EatPeach]

Some Update. I take the movement out without dial and hands and hour wheel. It runs pretty good and stop after 40+ hours. There's only half turn of the mainspring remain to be release, I think that's pretty normal. So I adjusted the hands make sure they dont touch each other and casing it once again. We'll see how far this time the watch can run. One thing I noticed is that although the amplitude doesnt change in the case or out the case, the rate is significantly different. In the case the rate is losing a bit and the positional variation is bigger.